Fix OpenSSL template

OpenSSL certificate should default to FQDN if possible.
Using IP addresses is not recommended, complicates dual stack
and limits addressing flexibility.

IPv6 control plane implementation [1] follow-up.

[1] Ia34e6916ea4f99e9522cd2ddde03a0a4776f7e2c

Change-Id: Ibfc02f933ddcc170e9d616d401e294ba0ff5e981

ansible/roles/certificates/templates/openssl-kolla.cnf.j2

@@ -13,10 +13,8 @@ commonName = {{ kolla_external_fqdn }}
 subjectAltName = @alt_names
 
 [alt_names]
-IP.1 = {{ kolla_external_vip_address }}
-# NOTE(Xing Zhang): Add IPv6 external VIP address to IP.2 when
-# ipv6-control-plane is implemented.
-#IP.2 =
 {% if kolla_external_fqdn != kolla_external_vip_address %}
 DNS.1 = {{ kolla_external_fqdn }}
+{% else %}
+IP.1 = {{ kolla_external_fqdn }}
 {% endif %}